Meeting Abstract
Animal social organization (size, composition of groups) plays an important role in social interactions that affect the fitness of individuals. Most studies report a single type of social organization for each species. This is problematic because intraspecific variation in social organization has been documented in mammals. Using Web of Science, we conducted primary literature searches to determine intraspecific variation in social organization of whales (Cetaceans) and dolphins (Pinnipedia). Intraspecific variation within and between populations of whales (n=19/23) and dolphins (n=31/33) is the norm. In whales, intraspecific variation in social organization includes singletons and groups of varying size (2 to 100s); composition is rarely reported. In dolphins, social organization is more often reported and intraspecific variation includes singletons (n= 24/33), single-sexed groups (both male and female; n= 31/33), and mixed-sexed groups (n= 30/33). Fission-fusion societies (size, composition of social groups frequently change) are reported in three dolphin species. In both whales and dolphins, group size varies with different behavioral strategies (e.g. migration, feeding). These results suggest intraspecific variation in marine mammal social organization is an important part of their biology. A phylogenetic study of marine mammal social organization is critical to a comprehensive understanding of the evolution of intraspecific variation in marine mammals.
